THE OLD WORLD MONKEYS 53
transverse ridges, but no oblique ridges connect the inetacones and protocones. The lower molars bear four cusps connected by transverse ridges, but no oblique ridges are present as in the upper molars; on their posterior parts there are talons or subsidiary cusps.
Vertebral Column.—The thoraco-lumbar vertebra? converge to a centre of motion, which is situated at the tenth dorsal vertebra; but there is no anti-clinal vertebra in the Anthropoid Apes. The vertebral formula is 07. D12-14. L5 to 7. S3. C3-26. Of the twelve to fourteen ribs eight are directly attached to the sternum by cartilages. A variable number of dorsal vertebrae have anapophyseal tubercles jutting from the pedicles; and the lumbar vertebrae frequently possess them too. The spine of the axis may be long. The caudal vertebrae possess chevron bones in tailed Monkeys.
The iliac bones are long and narrow, and are connected by a long pubic and ischiadic symphysis. The ischial tuberosities are everted, or form broad, flat plates for the support of the ischial callosities. The pelvic cavity is narrow.
The sternum is a narrow rod composed of six to eight sternebrse, and the manubrium is well marked. Vrolik (217) stated erroneously that there is no manubrium in the Mandrill.
The clavicle is straight at its sternal end, but the acromial end is concave forwards, with a large tubercle. The scapula is broad, with a small acromion process. The humerus has a prominent pectoral crest (outer lip of the bicipital groove) but no entepicondylar foramen. The carpus has an os centrale.
As in all Primates the radius and ulna can move on